STP not working

[sanketgroup]

Hello
I have installed SoftEther server on windows 7 on site A.
and
SoftEther Bridge on windows 7 on site B.

On site B bridge PC, NIC1 is Internet and NIC2 is connected to managed switch port#13.
STP is enabled on managed switch
but managed switch port#13 does not get STP information (from SoftEther Bridge PC NIC2)
Managed switch set that port in forwarding mode (as of cable is connected to Endpoint Client PC)
Actual that pc is not regular client pc, because it passes all local traffic of site B received on NIC2 to NIC1(Internet) to Site A.
So NIC2 is like bridge.
How can i resolve this STP issue so that managed switch can see it as root port.

Thanx

[thisjun]

Could you explain about site A?

[sanketgroup]

Discussion is ongoing at
http://www.vpnusers.com/viewtopic.php?f=7&t=6660